JWeb之Request

最新推荐文章于 2022-05-28 22:19:24 发布

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最新推荐文章于 2022-05-28 22:19:24 发布

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分类专栏： Java 文章标签： request JWeb

本文链接：https://blog.youkuaiyun.com/FloatDreamed/article/details/96893530

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本文主要探讨了JWeb中Request的使用，从前端页面到Servlet配置，详细解析了请求过程。通过实例展示了如何获取和处理GET及POST请求，包括表单数据与URL参数。通过对Request对象的方法介绍，帮助读者掌握在实际开发中的应用。

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一.前端页面

<%--
  Created by IntelliJ IDEA.
  User: WHW
  Date: 2019/7/21
  Time: 10:30
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
  <head>
    <title>$Title$</title>
  </head>
  <body>
  <fieldset>
    <button><a href="http://127.0.0.1:8080/rrr/user?username=Jhon&password=10">GetRequest</a></button>
  </fieldset>
  <fieldset>
    <form action="http://127.0.0.1:8080/rrr/user" method="post">
      用户名:<input type="text" name="username"/><br/>
      密　码:<input type="text" name="password"/><br/>
      <input type="submit" value="提交">
    </form>
  </fieldset>
  </body>
</html>

二.webxml配置

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
         http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">
    <servlet>
        <servlet-name>user</servlet-name>
        <servlet-class>controller.UserServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>user</servlet-name>
        <url-pattern>/user/*</url-pattern>
    </servlet-mapping>
</web-app>

三.Servlet类的配置

package controller;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.Map;

/**
 * @Author weihuanwen
 * @Date 2019/7/22 19:18
 * @Version 1.0
 */
public class UserServlet extends HttpServlet {

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        StringBuffer requestURL = request.getRequestURL();
        System.out.println("requestURL ::: "+requestURL);
        String requestURI = request.getRequestURI();
        System.out.println("requestURI ::: "+requestURI);
        String queryString = request.getQueryString();
        System.out.println("queryString ::: "+queryString);
        String pathInfo = request.getPathInfo();
        System.out.println("pathInfo ::: "+pathInfo);
        String remoteAddr = request.getRemoteAddr();
        System.out.println("remoteAddr ::: "+remoteAddr);
        String remoteHost = request.getRemoteHost();
        System.out.println("remoteHost ::: "+remoteHost);
        int remotePort = request.getRemotePort();
        System.out.println("remotePort ::: "+remotePort);
        String localAddr = request.getLocalAddr();
        System.out.println("localAddr ::: "+localAddr);
        String localName = request.getLocalName();
        System.out.println("localName ::: "+localName);
        Map<String, String[]> parameterMap = request.getParameterMap();
        for (String key : parameterMap.keySet()) {
            for (String value : parameterMap.get(key)) {
                System.out.println("[key:value] ::: ["+key+":"+value+"]");
            }
        }
    }
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request, response);
    }

}

四.测试

1.工程启动后网页界面如下:

2.点击GetRequest按钮,控制台输出如下:

requestURL ::: http://127.0.0.1:8080/rrr/user
requestURI ::: /rrr/user
queryString ::: username=Jhon&password=10
pathInfo ::: null
remoteAddr ::: 127.0.0.1
remoteHost ::: 127.0.0.1
remotePort ::: 51406
localAddr ::: 127.0.0.1
localName ::: www.howie.com
[key:value] ::: [username:Jhon]
[key:value] ::: [password:10]

3.填写表单,提交,控制台输出如下:

requestURL ::: http://127.0.0.1:8080/rrr/user
requestURI ::: /rrr/user
queryString ::: username=Jhon&password=10
pathInfo ::: null
remoteAddr ::: 127.0.0.1
remoteHost ::: 127.0.0.1
remotePort ::: 51406
localAddr ::: 127.0.0.1
localName ::: www.howie.com
[key:value] ::: [username:Jhon]
[key:value] ::: [password:10]

四.Request的相关方法介绍

调整servlet的代码如下:


   protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        StringBuffer requestURL = request.getRequestURL();
        System.out.println("requestURL ::: "+requestURL);
        String requestURI = request.getRequestURI();
        System.out.println("requestURI ::: "+requestURI);
        String queryString = request.getQueryString();
        System.out.println("queryString ::: "+queryString);
        String pathInfo = request.getPathInfo();
        System.out.println("pathInfo ::: "+pathInfo);
        String remoteAddr = request.getRemoteAddr();
        System.out.println("remoteAddr ::: "+remoteAddr);
        String remoteHost = request.getRemoteHost();
        System.out.println("remoteHost ::: "+remoteHost);
        int remotePort = request.getRemotePort();
        System.out.println("remotePort ::: "+remotePort);
        String localAddr = request.getLocalAddr();
        System.out.println("localAddr ::: "+localAddr);
        String localName = request.getLocalName();
        System.out.println("localName ::: "+localName);
        String acceptEncoding = request.getHeader("Accept-Encoding");
        System.out.println("acceptEncoding ::: "+acceptEncoding);
        Enumeration<String> headers = request.getHeaders("Host");
        while (headers.hasMoreElements()){
            String value = headers.nextElement();
            System.out.println("Host ::: "+value);
        }
        Enumeration<String> headerNames = request.getHeaderNames();
        while (headerNames.hasMoreElements()){
            String headerName = headerNames.nextElement();
            System.out.println("headName ::: "+headerName);
        }
        String username = request.getParameter("username");
        System.out.println("username ::: "+ username);

        String[] hobbies = request.getParameterValues("hobby");
        System.out.println(Arrays.toString(hobbies));

        Map<String, String[]> parameterMap = request.getParameterMap();
        for (String key : parameterMap.keySet()) {
            for (String value : parameterMap.get(key)) {
                System.out.println("[key:value] ::: ["+key+":"+value+"]");
            }
        }
    }

测试请求路径为:http://127.0.0.1:8080/rrr/user/XX/YY?username=Jhon&password=10&hobby=read&hobby=sing

测试结果如下:

requestURL ::: http://127.0.0.1:8080/rrr/user/XX/YY
requestURI ::: /rrr/user/XX/YY
queryString ::: username=Jhon&password=10&hobby=read&hobby=sing
pathInfo ::: /XX/YY
remoteAddr ::: 127.0.0.1
remoteHost ::: 127.0.0.1
remotePort ::: 52528
localAddr ::: 127.0.0.1
localName ::: www.howie.com
acceptEncoding ::: gzip, deflate
Host ::: 127.0.0.1:8080
headName ::: host
headName ::: user-agent
headName ::: accept
headName ::: accept-language
headName ::: accept-encoding
headName ::: connection
headName ::: upgrade-insecure-requests
username ::: Jhon
[read, sing]
[key:value] ::: [username:Jhon]
[key:value] ::: [password:10]
[key:value] ::: [hobby:read]
[key:value] ::: [hobby:sing]

方法名	描述	Result
getRequestURL()	返回客户段发出请求时的完整URL地址	http://127.0.0.1:8080/rrr/user
getRequestURI()	返回请求行中的资源名部分	/rrr/user
getQueryString()	返回请求行中的参数部分	username=Jhon&password=10
getPathInfo()	返回请求路径URL中Servlet路径以后参数以前的路径信息	/XX/YY
getRemoteAddr()	返回发出请求的客户机的IP地址	127.0.0.1
getRemoteHost()	返回发出请求的客户机的完整主机名	127.0.0.1
getRemotePort()	返回客户机所使用的网络端口号	51691
getLocalAddr()	返回WEB服务器的IP地址	127.0.0.1
getLocalName()	返回WEB服务器的主机名(本例中主机名为host文件配置)	www.howie.com
getHeader(string name)	获取头信息指定请求头名的信息	gzip, deflate
getHeaders(String name)	获取多组请求头名称相同的其中一组信息(这里只有一组)	127.0.0.1:8080
getHeaderNames()	获取所有头信息中请求头名称	user-agent .......... upgrade-insecure-requests
getParameter(String name)	获取指定参数名的参数值	Jhon
getParameterValues(String name)	获取相同参数名下的多个值(返回值为String[])	[read, sing]
getParameterMap()	获取所有参数信息(以map形式封装)	[username:Jhon] [password:10] [hobby:read] [hobby:sing]